You know that strange blue contraption lurking in the corner of your gym, the one that sort of resembles a stability ball cut in half? Well, it’s called a BOSU® Balance Trainer, and it happens to be one of the most powerful, versatile fitness products on the market.
If you haven’t already, now is the time to make friends with the underrated but uber-effective BOSU®. The secret to the contraption lies in its dual-sided design. With an inflated squishy half-dome on one side and a solid black platform on the other, the BOSU® (which is an acronym for “Both Sides Utilized”) provides an unstable surface on which to train. Imagine running on a beach—the soft, uneven sand activates different leg muscles than running on stable pavement (read: aching calves the next day). Similarly, training on a BOSU® forces every single muscle to work hard to stabilize the body. The end result: a shredded core, better balance and a rockin’ physique. Sound enticing? We thought so.
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In their new book Weights on the BOSU® Balance Trainer: Strengthen and Tone All Your Muscles with Unstable Workouts, trainers Brett Stewart and Jason Warner lay out a comprehensive, day-by-day workout program centered around the BOSU. Just in time for summer, we’ve handpicked seven basic BOSU moves that can be incorporated into any workout routine. Go ahead, flaunt that bikini!
1) BOSU® Push-up
Works chest, shoulders, arms, back, core

Get on your hands and knees and position your hands on either side of the circle at the center of the ball, arms fully extended. Find a placement that feels comfortable—not too wide, not too narrow. Lift your knees off the floor, tightening your core to support your whole body. (Stay on your knees if this is too challenging.)

Lie with your upper back supported on the circle at the center of the ball, knees bent and feet firmly planted on the floor slightly wider than your shoulders. Grasp a dumbbell with each hand and curl the weights into position at chest level, with your thumbs parallel with your chest. Engage your core, squeeze your glutes together and press your hips toward the ceiling to form a bridge position, with your torso parallel to the floor and flat from chest to knees.

With the BOSU Balance Trainer approximately half a stride’s length in front of you, stand upright with a dumbbell in each hand, arms fully extended at your sides.

Place your right toes directly in the middle of the bull’s-eye with your right knee bent slightly. Support your weight on your left leg, with most of it through your heel, not your toes.

Bend your right leg and begin to lower your left knee to the ground and pause. Push through your right heel and return to starting position. Switch sides. Do 3 sets of 6 reps on each leg.

5) BOSU® Plank
Works abs, lower back, glutes, hips, obliques

Get on your knees and put your hands on the dome under your chest on both sides of the circle in the center of theball. Lift your knees off the floor. Only your toes and hands should be supporting your full weight. Engage your core, keeping a straight line from your heels to head. Hold this position for 30 seconds. Repeat 3 times.

6) BOSU® Mason Twist
Works core

Sit comfortably in the middle of the dome and either hold a weight with both hands or clasp your hands together. Using your core, lift your legs off the ground, knees bent slightly. Keep your heels approximately 3–6 inches off the ground for the duration.

Lie on the ground with your feet on the circle at the center of the ball and your knees bent. Balance a weight on your hips, keeping it in place with your hands. Engage your core, and squeeze your glutes together.

Pushing through your heels, raise your hips upward until fully extended. Your body should form a straight line from sternum to knees; your upper back, head and shoulders should remain on the ground with your arms and hands. Pause.